The problem with locks is that there is always a key to open them. No matter how secure you make them, you still have to make it accessible to the person who owns it. Because of this feature or flaw, anyone with the key can open a lock.
Technology locks are a little different. Apple says that they have no way to unlock a device because the customer is the one who creates the key. Thus only the customer can unlock it. Now Tim Cook, Apple's CEO, is viewed as a hero and a fierce advocate for privacy.
At the end of the day we still need a key to unlock the phone, and the customer has that key. Worst when the device is locked with a pin, only four digits are needed to unlock it. (brute force anyone?)
There are two ways to unlock any authentication system, whether it's a physical lock, or software protection. One is to find a design flaw, which somebody always finds some how, remember heartbleed? The other is to use the key to unlock it. Social engineering, or clever tricks to get the owner of the key to hand it over. Or beat him up into submission.(torture, or threats, let's not pretend this doesn't happen)
The point is, if there is a single way for a person to legitimately open the lock, then there is a way to open the lock for others.
This brings us back to a fundamental problem of life. Nothing is safe. Just because you wear a helmet, or a seat-belt doesn't mean you won't get hurt. All they do is help you increase your chances of survival, but never eliminate the problem entirely.
A lock keeps honest people honest. When you use a password to lock your computer, it may keep your family and friends at bay, but a dedicated identity thief might find ways to get in.
The only way the lock on your door is protecting you, is that the thief knows that if he is caught breaking in he will have to face the law. On the web, it is much harder to identify the thief, giving them more protection. The fact that Apple cannot unlock their own device is a step in the right direction, even if it doesn't provide omniprotection.
Just remember all locks are never 100% secure. That's just the way it is.